Systems and methods to improve timestamp transition resolution

ABSTRACT

Example methods and apparatus to improve timestamp transition resolution of watermarks are disclosed. A disclosed example apparatus is to determine an initial resolution for timestamp transitions based on a first number of time units between first ones of watermarks detected in media, and determine an updated resolution for the timestamp transitions based on a predicted timestamp transition window and a second number of time units between second ones of the watermarks detected in the media, the second ones of the watermarks to be subsequent to the first ones of the watermarks in the media, the predicted timestamp transition window associated with the initial resolution for time stamp transitions, the updated resolution for the timestamp transitions corresponding to a third number of time units, the third number of time units less than the second number of time units.

RELATED APPLICATIONS

This patent arises from a continuation of U.S. patent application Ser.No. 17/365,842, titled “SYSTEMS AND METHODS TO IMPROVE TIMESTAMPTRANSITION RESOLUTION,” filed Jul. 1, 2021, which is a continuation ofU.S. patent application Ser. No. 16/943,715, titled “SYSTEMS AND METHODSTO IMPROVE TIMESTAMP TRANSITION RESOLUTION,” filed Jul. 30, 2020, whichis a continuation of U.S. patent application Ser. No. 16/450,057, titled“SYSTEMS AND METHODS TO IMPROVE TIMESTAMP TRANSITION RESOLUTION,” filedJun. 24, 2019, which is a continuation of U.S. patent application Ser.No. 15/800,466, titled “SYSTEMS AND METHODS TO IMPROVE TIMESTAMPTRANSITION RESOLUTION,” filed Nov. 1, 2017, which claims the benefitunder 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No.62/573,798, which was filed on Oct. 18, 2017. Priority to U.S. patentapplication Ser. No. 17/365,842, U.S. patent application Ser. No.16/943,715, U.S. patent application Ser. No. 16/450,057, U.S. patentapplication Ser. No. 15/800,466, and U.S. Provisional Patent ApplicationNo. 62/573,798 is claimed. U.S. patent application Ser. No. 17/365,842,U.S. patent application Ser. No. 16/943,715, U.S. patent applicationSer. No. 16/450,057, U.S. patent application Ser. No. 15/800,466, andU.S. Provisional Patent Application No. 62/573,798 are herebyincorporated herein by reference in their entireties.

FIELD OF THE DISCLOSURE

This disclosure relates generally to media watermarking, and, moreparticularly, to systems and methods to improve timestamp transitionresolution.

BACKGROUND

Watermarks can be embedded or otherwise included in media to enableadditional information to be conveyed with the media. For example, audiowatermarks can be embedded or otherwise included in the audiodata/signal portion of a media stream, file and/or signal to conveydata, such as media identification information, copyright protectioninformation, timestamps indicative of broadcast time, etc., with themedia. Such watermarks enable monitoring of the distribution and/or useof media, such as by detecting watermarks present in televisionbroadcasts, radio broadcasts, streamed multimedia, etc., to identify theparticular media being presented to viewers, listeners, users, etc. Suchinformation can be valuable to advertisers, content providers, and thelike.

Prior media monitoring systems employing watermarks typically includewatermark decoders that identify the information contained in thewatermarks. Some prior systems identify the timestamps in the watermarksand transitions between timestamps to a relatively coarse resolution,such as a resolution of one minute.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example media monitoring system, whichincludes an example timestamp transition resolution enhancer constructedin accordance with the teachings of this disclosure.

FIG. 2 illustrates an example watermark to be detected by the examplemedia device monitor of FIG. 1 .

FIG. 3 a block diagram illustrating an example implementation of thetimestamp transition resolution enhancer of FIG. 1 .

FIG. 4 illustrates an example mapping of detected watermarks,timestamps, and timestamp transition resolution enhancement performed inaccordance with the teachings of this disclosure.

FIG. 5 is a flowchart representative of first example machine readableinstructions that may be executed to implement the example mediamonitoring system of FIG. 1 and/or the example timestamp transitionresolution enhancer of FIG. 3 .

FIG. 6 is a block diagram of an example processor platform structured toexecute the example machine readable instructions of FIG. 5 to implementthe example media monitoring system of FIG. 1 and/or the exampletimestamp transition resolution enhancer of FIG. 3 .

The figures are not to scale. Wherever possible, the same referencenumbers will be used throughout the drawing(s) and accompanying writtendescription to refer to the same or like parts.

DETAILED DESCRIPTION

Systems, methods, apparatus, and articles of manufacture (e.g.,non-transitory, physical storage media) to improve timestamp transitionresolution in watermarks are disclosed herein. Example watermarktimestamp transition resolution enhancing systems include a watermarkdetector to detect watermarks and a decoder to decode timestamps inrespective ones of the watermarks. Some such example systems alsoinclude a timestamp transition resolution enhancer to estimate a firsttransition window indicative of a transition between a first time periodto a second time period based on a first one of the timestamps and asecond one of the timestamps. In some examples, the timestamp transitionresolution enhancer also estimates, when the first transition windowdoes not satisfy a threshold, a second transition window indicative of atransition between the second time period and a third time period basedon the second timestamp and a third one of the timestamps. In addition,the example timestamp transition resolution enhancer of some examplesdetermines a first mapped transition window based on an intersection ofthe first transition window and the second transition window and setsthe first mapped transition window as a reference time transition windowfor subsequent time periods.

In some examples, the timestamp transition resolution enhancer is to setthe first transition window as an established time transition when thefirst transition window satisfies the threshold.

In some examples, the timestamp transition resolution enhancer is to setthe first mapped transition window as an established time transitionwhen the first mapped transition window satisfies the threshold.

In some examples, the timestamp transition resolution enhancer is toestimate, when the first mapped transition window does not satisfy thethreshold, a third transition window indicative of a transition betweenthe third time period and a fourth time period of time based on thethird timestamp and a fourth one of the timestamps. In such examples,the timestamp transition resolution enhancer also is to determine asecond mapped transition window based on an intersection of the firstmapped transition window and the third transition window and set thesecond mapped transition window as the reference time transition window.

In some examples, the timestamp transition resolution enhancer is to setthe second mapped transition window as an established time transitionwhen the second mapped transition window satisfies the threshold.

In some examples, the timestamp transition resolution enhancer is to setan established time transition based on at least one of the firsttransition window or the first mapped transition window satisfying thethreshold. In such examples, the timestamp transition resolutionenhancer also is to retroactively map time transitions in the mediasignal based on the established time transition.

In some examples, respective ones of the time periods have minutedurations and the threshold is about five seconds.

In some examples, the first transition window is identified when a firsttimestamp in a first watermark is different than a second timestamp in asecond watermark.

Also disclosed herein are example methods that include estimating, byexecuting an instruction with a processor, a first transition windowindicative of a transition between a first time period to a second timeperiod based on a first timestamp of a first watermark and a secondtimestamp of a second watermark. Some such example methods also includeestimating, by executing an instruction with a processor when the firsttransition window does not satisfy a threshold, a second transitionwindow indicative of a transition between the second time period and athird time period based on the second timestamp and a third timestamp.In addition, some example methods include determining, by executing aninstruction with a processor, a first mapped transition window based onan intersection of the first transition window and the second transitionwindow and setting the first mapped transition window as the referencetime transition window for subsequent time periods.

Some example methods also include setting, by executing an instructionwith a processor, the first transition window as an established timetransition when the first transition window satisfies the threshold.

Some example methods also include setting, by executing an instructionwith a processor, the first mapped transition window as an establishedtime transition when the first mapped transition window satisfies thethreshold.

Some example methods also include estimating, by executing aninstruction with a processor when the first mapped transition windowdoes not satisfy the threshold, a third transition window indicative ofa transition between the third time period and a fourth time period oftime based on the third timestamp and a fourth timestamp. Such examplemethods also include determining, by executing an instruction with aprocessor, a second mapped transition window based on an intersection ofthe first mapped transition window and the third transition window andsetting the second mapped transition window as the reference timetransition window.

Some example methods include setting, by executing an instruction with aprocessor, the second mapped transition window as an established timetransition when the second mapped transition window satisfies thethreshold.

Some example methods include setting, by executing an instruction with aprocessor, an established time transition based on at least one of thefirst transition window or the first mapped transition window satisfyingthe threshold. Such example methods also include retroactively mapping,by executing an instruction with a processor, time transitions in themedia signal based on the established time transition.

Some example methods also include respective ones of the time periodshave minute durations and the threshold is about five seconds.

Some example methods also include comparing, by executing an instructionwith a processor, a first timestamp in a first watermark and a secondtime stamp in a second watermark and identifying, by executing aninstruction with a processor, the first transition window when the firsttimestamp and the second timestamp are different.

Also disclosed herein are non-transitory machine-readable storage mediacomprising machine-readable instructions which, when executed, cause amachine to at least: estimate a first transition window indicative of atransition between a first time period to a second time period based ona first timestamp of a first watermark and a second timestamp of asecond watermark. The example instructions of some such examples alsocause the machine to estimate, when the first transition window does notsatisfy a threshold, a second transition window indicative of atransition between the second time period and a third time period basedon the second timestamp and a third timestamp. In addition, the exampleinstructions of some such examples cause the machine to determine afirst mapped transition window based on an intersection of the firsttransition window and the second transition window and set the firstmapped transition window as the reference time transition window forsubsequent time periods.

In some examples, the instructions cause the machine to set the firsttransition window as an established time transition when the firsttransition window satisfies the threshold.

In some examples, the instructions further cause the machine to set thefirst mapped transition window as an established time transition whenthe first mapped transition window satisfies the threshold.

In some examples, the instructions further cause the machine toestimate, when the first mapped transition window does not satisfy thethreshold, a third transition window indicative of a transition betweenthe third time period and a fourth time period of time based on thethird timestamp and a fourth timestamp. In such examples, theinstructions also cause the machine to determine a second mappedtransition window based on an intersection of the first mappedtransition window and the third transition window and set the secondmapped transition window as the reference time transition window.

In some examples, the instructions further cause the machine to set thesecond mapped transition window as an established time transition whenthe second mapped transition window satisfies the threshold.

In some examples, the instructions further cause the machine to set anestablished time transition based on at least one of the firsttransition window or the first mapped transition window satisfying thethreshold and retroactively map time transitions in the media signalbased on the established time transition.

In some examples, respective ones of the time periods have minutedurations and the threshold is about five seconds.

In some examples, the instructions further cause the machine to identifythe first transition window when a first timestamp in a first watermarkis different than a second timestamp in a second watermark.

Also disclosed herein are example systems that include means fordetecting watermarks and means for decoding timestamps in respectiveones of the watermarks. Such example systems also includes means forestimating transition windows by estimating a first transition windowindicative of a transition between a first time period to a second timeperiod based on a first one of the timestamps and a second one of thetimestamps, and estimating, when the first transition window does notsatisfy a threshold, a second transition window indicative of atransition between the second time period and a third time period basedon the second timestamp and a third one of the timestamps. Such examplesystems also include means for determining a first mapped transitionwindow based on an intersection of the first transition window and thesecond transition window. In addition, such example systems includemeans for setting the first mapped transition window as a reference timetransition window for subsequent time periods.

In some example systems, the means for setting is to set the firsttransition window as an established time transition when the firsttransition window satisfies the threshold.

In some example systems, the means for setting is to set the firstmapped transition window as an established time transition when thefirst mapped transition window satisfies the threshold.

In some example systems, when the first mapped transition window doesnot satisfy the threshold, the means for estimating is to estimate athird transition window indicative of a transition between the thirdtime period and a fourth time period of time based on the thirdtimestamp and a fourth one of the timestamps. In such example systems,the means for determining is to determine a second mapped transitionwindow based on an intersection of the first mapped transition windowand the third transition window. In addition, in such examples, themeans for setting is to set the second mapped transition window as thereference time transition window.

In some examples systems, the means for setting is to set the secondmapped transition window as an established time transition when thesecond mapped transition window satisfies the threshold.

In some examples systems, the means for setting is to set an establishedtime transition based on at least one of the first transition window orthe first mapped transition window satisfying the threshold. In suchexample systems, the means for setting also is to retroactively map timetransitions in the media signal based on the established timetransition.

In some examples systems, respective ones of the time periods haveminute durations and the threshold is about five seconds.

In some examples systems, the means for estimating is to identify thefirst transition window when a first timestamp in a first watermark isdifferent than a second timestamp in a second watermark.

Also disclosed herein are systems that include a watermark detector todetect watermarks and a decoder to decode timestamps in respective onesof the watermarks. Some such example systems include a timestamptransition resolution enhancer to determine moments of transitionbetween time periods of media containing the watermarks based on thetimestamps by: (a) estimating a coarse transition window between twotime periods; (b) mapping a prior transition window estimate to theestimate of (a); (c) narrowing to a fine transition window estimatebased on an overlap between the estimate of (a) and (b); (d) comparingthe estimate of (c) to a threshold; (e) repeating (a) through (d) forsuccessive time periods using the fine transition window estimate of (c)as the prior transition window estimate of (b) until the fine transitionwindow estimate of (c) satisfies the threshold; and (e) establishing thefine transition window estimate as an established moment of transitionbetween time periods when the estimate of (c) satisfies the threshold.

In some examples, the timestamp transition resolution enhancer is toidentify the moments of transition between time periods of the mediasignal based on the established moment of transition.

In some examples, the time periods correspond to successive minutes ofthe media signal and the threshold is about five seconds.

Also disclosed herein are methods that include detecting, by executingan instruction with a processor, watermarks and decoding, by executingan instruction with a processor, timestamps in respective ones of thewatermarks. Some such example methods also include determining, byexecuting an instruction with a processor, moments of transition betweentime periods of media containing the watermarks based on the timestampsby: (a) estimating a coarse transition window between two time periods;(b) mapping a prior transition window estimate to the estimate of (a);(c) narrowing to a fine transition window estimate based on an overlapbetween the estimate of (a) and (b); (d) comparing the estimate of (c)to a threshold; (e) repeating (a) through (d) for successive timeperiods using the fine transition window estimate of (c) as the priortransition window estimate of (b) until the fine transition windowestimate of (c) satisfies the threshold; and (f) establishing the finetransition window estimate as an established moment of transitionbetween windows when the estimate of (c) satisfies the threshold.

In some examples, the method includes identifying, by executing aninstruction with a processor, the moments of transition between timeperiods of the media signal based on the established moment oftransition.

In some examples, the method includes the time periods corresponding tosuccessive minutes of the media signal and the threshold is about fiveseconds.

Also disclosed herein are non-transitory storage media includingmachine-readable instructions which, when executed, cause a machine toat least detect watermarks and decode timestamps in respective ones ofthe watermarks. In some examples, the instructions also cause themachine to determine moments of transition between time periods of mediacontaining the watermarks based on the timestamps by: (a) estimating acoarse transition window between two time periods; (b) mapping a priortransition window estimate to the estimate of (a); (c) narrowing to afine transition window estimate based on an overlap between the estimateof (a) and (b); (d) comparing the estimate of (c) to a threshold; (e)repeating (a) through (d) for successive time periods using the finetransition window estimate of (c) as the prior transition windowestimate of (b) until the fine transition window estimate of (c)satisfies the threshold; and (f) establishing the fine transition windowestimate as an established moment of transition between windows when theestimate of (c) satisfies the threshold.

In some examples, the instructions further cause the machine to identifythe moments of transition between time periods of the media signal basedon the established moment of transition.

In some examples, the time periods correspond to successive minutes ofthe media signal and the threshold is about five seconds.

Also disclosed herein are example systems that include means fordetecting watermarks and means for decoding timestamps in respectiveones of the watermarks. Such example systems also include means fordetermining moments of transition between time periods of mediacontaining the watermarks based on the timestamps by: (a) estimating acoarse transition window between two time periods; (b) mapping a priortransition window estimate to the estimate of (a); (c) narrowing to afine transition window estimate based on an overlap between the estimateof (a) and (b); (d) comparing the estimate of (c) to a threshold; (e)repeating (a) through (d) for successive time periods using the finetransition window estimate of (c) as the prior transition windowestimate of (b) until the fine transition window estimate of (c)satisfies the threshold; and (f) establishing the fine transition windowestimate as an established moment of transition between time periodswhen the estimate of (c) satisfies the threshold.

In some example systems, the means for determining is to identify themoments of transition between time periods of the media signal based onthe established moment of transition.

In some example systems, the time periods correspond to successiveminutes of the media signal and the threshold is about five seconds.

These and other example methods, apparatus, systems and articles ofmanufacture (e.g., physical storage media) to implement improvetimestamp transition resolution in watermarks in media are disclosed ingreater detail below.

As used herein, the term “media” includes any type of content and/oradvertisement delivered via any type of distribution medium. Thus, mediaincludes television programming or advertisements, radio programming oradvertisements, movies, web sites, streaming media, etc. Further, mediaincludes audio and/or visual (still or moving) content and/oradvertisements.

Example methods, apparatus, and articles of manufacture disclosed hereinmonitor media presentations at media devices. Such media devices mayinclude, for example, Internet-enabled televisions, personal computers,Internet-enabled mobile handsets (e.g., a smartphone), video gameconsoles (e.g., Xbox®, PlayStation®), tablet computers (e.g., an iPad®),digital media players (e.g., a Roku® media player, a Slingbox®, etc.),etc. In some examples, media monitoring information is aggregated todetermine ownership and/or usage statistics of media devices, relativerankings of usage and/or ownership of media devices, types of uses ofmedia devices (e.g., whether a device is used for browsing the Internet,streaming media from the Internet, etc.), and/or other types of mediadevice information. In examples disclosed herein, monitoring informationincludes, but is not limited to, media identifying information (e.g.,media-identifying metadata, codes, signatures, watermarks, and/or otherinformation that may be used to identify presented media), applicationusage information (e.g., an identifier of an application, a time and/orduration of use of the application, a rating of the application, etc.),and/or user-identifying information (e.g., demographic information, auser identifier, a panelist identifier, a username, etc.).

Audio watermarking is a technique used to identify media such astelevision broadcasts, radio broadcasts, advertisements (televisionand/or radio), downloaded media, streaming media, prepackaged media,etc. Existing audio watermarking techniques identify media by embeddingone or more audio codes (e.g., one or more watermarks), such as mediaidentifying information and/or an identifier that may be mapped to mediaidentifying information, into an audio and/or video component. In someexamples, the audio or video component is selected to have a signalcharacteristic sufficient to hide the watermark. As used herein, theterms “code” or “watermark” are used interchangeably and are defined tomean any identification information (e.g., an identifier) that may beinserted or embedded in the audio or video of media (e.g., a program oradvertisement) for the purpose of identifying the media or for anotherpurpose such as tuning (e.g., a packet identifying header). To identifywatermarked media, the watermark(s) are extracted and used to access atable of reference watermarks that are mapped to media identifyinginformation.

Unlike media monitoring techniques based on codes and/or watermarksincluded with and/or embedded in the monitored media, fingerprint orsignature-based media monitoring techniques generally use one or moreinherent characteristics of the monitored media during a monitoring timeinterval to generate a substantially unique proxy for the media. Such aproxy is referred to as a signature or fingerprint, and can take anyform (e.g., a series of digital values, a waveform, etc.) representativeof any aspect(s) of the media signal(s) (e.g., the audio and/or videosignals forming the media presentation being monitored). A signature maybe a series of signatures collected in series over a timer interval. Agood signature is repeatable when processing the same media presentationbut is unique relative to other (e.g., different) presentations of other(e.g., different) media. Accordingly, the term “fingerprint” and“signature” are used interchangeably herein and are defined herein tomean a proxy for identifying media that is generated from one or moreinherent characteristics of the media.

Signature-based media monitoring generally involves determining (e.g.,generating and/or collecting) signature(s) representative of a mediasignal (e.g., an audio signal and/or a video signal) output by amonitored media device and comparing the monitored signature(s) to oneor more references signatures corresponding to known (e.g., reference)media sources. Various comparison criteria, such as a cross-correlationvalue, a Hamming distance, etc., can be evaluated to determine whether amonitored signature matches a particular reference signature. When amatch between the monitored signature and one of the referencesignatures is found, the monitored media can be identified ascorresponding to the particular reference media represented by thereference signature that with matched the monitored signature. Becauseattributes, such as an identifier of the media, a presentation time, abroadcast channel, etc., are collected for the reference signature,these attributes may then be associated with the monitored media whosemonitored signature matched the reference signature. Example systems foridentifying media based on codes and/or signatures are long known andwere first disclosed in Thomas, U.S. Pat. No. 5,481,294, which is herebyincorporated by reference in its entirety.

As noted above, watermarks can be embedded or otherwise included inmedia to enable additional information to be conveyed with the media.This information can include timestamps that indicate the time at whicha portion of the media signal containing the watermark was broadcast.Timestamps are important for advertisers, for example, to verify thebroadcast of their content. Timestamps are also important in mediamonitoring to identify the moments in time an audience member wasexposed to particular media.

The timestamps embedded in watermarks change with the time of day andwith a given time resolution. Thus, a timestamp at one minute may be T1and the next minute may be T2 (e.g., T1 plus one minute). Comparing onewatermark to the next would indicate when the time switched from T1 toT2. However, at times the watermarks cannot be detected based on, forexample, noise obscuring the media signal. Thus, many watermarks goundetected. When two detected timestamps indicate a change in time fromT1 to T2 but there are undetected watermarks in between the twowatermarks, the analysis will not indicate precisely when the timechanged from T1 to T2. Though timestamps that are encoded in watermarksmay be accurate to the second, traditional systems only have a timetransition window resolution of one minute. That is, known systems canonly estimate a time change in increments of one minute.

Examples disclosed herein improve the time transition window resolution.For example, in a media signal in which the timestamp code is repeatedevery 4.8 seconds, there are twelve to thirteen opportunities to detectthe timestamp per minute. As disclosed herein, the resolution of thetime transition window estimate is improved to, for example, about fiveseconds. As used herein, “about” means+/−0.2 seconds. This improvementprovides more accurate estimation of broadcast time and more valuableinformation. For example, some advertisements are included in broadcastslots or spots of less than a minute including, for example, ten-second,fifteen-second, or thirty-second spots. When the timestamp transitionresolution is only precise to a minute, the exact timing of a sub-minutelong broadcast cannot be determined accurately based on such knownwatermarks.

Turning to the figures, a block diagram of an example media monitoringsystem 100 implementing improved timestamp transition resolution fromwatermarks in media signals as disclosed herein is illustrated in FIG. 1. The example media monitoring system 100 of FIG. 1 supports monitoringof media presented at one or more monitored sites, such as an examplemonitored site 105 illustrated in FIG. 1 . The monitored site 105includes an example media device 110, which is also referred to hereinas a media presentation device 110. Although the example of FIG. 1illustrates one monitored site 105 and one media device 110, improvedtimestamp transition resolution from watermarks in media signals asdisclosed herein can be implemented in media monitoring systems 100supporting any number of monitored sites 105 having any number of mediadevices 110.

The media monitoring system 100 of the illustrated example includes anexample media device meter 125 (also referred to as a meter 125, a sitemeter 125, a site unit 125, a home unit 125, a portable device 125,etc.) to monitor media presented by the media device 110. In theillustrated example, the media monitored by the media device meter 125can correspond to any type of media presentable by the media device 110.For example, monitored media can correspond to media content, such atelevision programs, radio programs, movies, Internet video,video-on-demand, etc., as well as commercials, advertisements, etc. Inthe illustrated example, the media device meter 125 determines meteringdata including timestamps that may identify and/or be used to identifymedia presented by the media device and the corresponding times (and,thus, infer media exposure) at the monitored site 105. The media devicemeter 125 then stores and reports this metering data via an examplenetwork 135 to an example data processing facility 140. The dataprocessing facility 140 performs any appropriate post-processing of themetering data to, for example, determine audience ratings information,identify targeted advertising to be provided to the monitored site 105,etc. In the illustrated example, the network 135 can correspond to anytype(s) and/or number of wired and/or wireless data networks, or anycombination thereof.

In the illustrated example, the media device 110 monitored by the mediadevice meter 125 can correspond to any type of audio, video and/ormultimedia presentation device capable of presenting media audiblyand/or visually. For example, the media device 110 can correspond to atelevision and/or display device that supports the National TelevisionStandards Committee (NTSC) standard, the Phase Alternating Line (PAL)standard, the Systéme Electronique pour Couleur avec Mémoire (SECAM)standard, a standard developed by the Advanced Television SystemsCommittee (ATSC), such as high definition television (HDTV), a standarddeveloped by the Digital Video Broadcasting (DVB) Project, etc. As otherexamples, the media device 110 can correspond to a multimedia computersystem, a personal digital assistant, a cellular/mobile smartphone, aradio, a tablet computer, etc.

In the media monitoring system 100 of the illustrated example, the mediadevice meter 125 and the data processing facility 140 cooperate toperform media monitoring based on detected media watermarks. Moreover,the media device meter 125 implements improved timestamp transitionresolution as disclosed herein. Examples of watermarks includeidentification codes, ancillary codes, etc., that may be transmittedwithin media signals. For example, identification codes can betransmitted as watermarked data embedded or otherwise included withmedia (e.g., inserted into the audio, video, or metadata stream ofmedia) to uniquely identify broadcasters and/or media (e.g., content oradvertisements). Watermarks can additionally or alternatively be used tocarry other types of data, such as copyright protection information,secondary data (e.g., such as one or more hyperlinks pointing tosecondary media retrievable via the Internet and associated with theprimary media carrying the watermark), commands to control one or moredevices, etc. Watermarks are typically extracted using a decodingoperation.

In the illustrated example of FIG. 1 , the media device meter 125 isimplemented by a portable device including an example watermark detector145 and an example timestamp transition resolution enhancer 150. In theillustrated example, the watermark detector 145 is configured to detectwatermark(s) in media signal(s) output from a monitored media device,such as the example media device 110. In the illustrated example, thetimestamp transition resolution enhancer 150 is configured to improvethe timestamp transition resolution of the watermarks detected by thewatermark detector 145. In some examples, the media device meter 125corresponds to a special purpose portable device constructed toimplement the example watermark detector 145 and the example timestamptransition resolution enhancer 150. In other examples, the media devicemeter 125 corresponds to any portable device capable of being adapted(via hardware changes, software changes, firmware changes, or anycombination thereof) to implement the example watermark detector 145 andthe example timestamp transition resolution enhancer 150. As such, themedia device meter 125 can be implemented by a smartphone, a tabletcomputer, a handheld device, a wrist-watch type device (e.g., a smartwatch such as the Apple Watch sold by Apple Inc.), other wearabledevices, a special purpose device, etc. In some examples, the mediadevice meter 125 can be implemented by a portable device that, althoughportable, is intended to be relatively stationary. Furthermore, in someexamples, the media device meter 125 can be implemented by, or otherwiseincluded in, the media device 110, such as when the media device 110corresponds to a portable device (e.g., a smartphone, a tablet computer,a handheld device, etc.) capable of presenting media. This latterimplementation can be especially useful in example scenarios in which amedia monitoring application is executed on the media device 110 itself,but the media device 110 prevents, e.g., via digital rights managementor other techniques, third-party applications, such as the mediamonitoring application, from accessing protected media data stored onthe media device 110. An example implementation of the media devicemeter 125 is illustrated in FIG. 3 , which is described in furtherdetail below. Though described as incorporated with the media devicemeter 125, the timestamp transition resolution enhancer 150 may beincorporated additionally or alternatively with the data processingfacility 140. Furthermore, in some examples, the media device meter 125may additionally collect signatures.

FIG. 2 illustrates an example watermark 200 that the example mediadevice meter 125 may be configured to detect. The watermark 200 of theillustrated is embedded or otherwise included in media to be presentedby media device(s), such as the example media device 110. For example,the watermark 200 may be embedded in an audio portion (e.g., an audiodata portion, an audio signal portion, etc.) of the media, a videoportion (e.g., a video data portion, a video signal portion, etc.) ofthe media, or a combination thereof. The example watermark 200 of FIG. 2includes an example first group of symbols 205 and an example secondgroup of symbols 210. In the illustrated example of FIG. 2 , the firstgroup of symbols 205 is repeated in successive watermarks 200embedded/included in the media, whereas the second group of symbols 210,which is indicative of a broadcast time, differs between successivewatermarks 200 embedded/included in the media.

In the example watermark of FIG. 2 , the first group of symbols 205conveys media identification data (e.g., a media identifier) identifyingthe media watermarked by the watermark 200. For example, the mediaidentification data conveyed by the first group of symbols 205 mayinclude data identifying a broadcast station providing the media, a name(e.g., program name) of the media, a source (e.g., a website) of themedia, etc. Thus, in the illustrated example of FIG. 2 , the first groupof symbols 205 is also referred to as a first group of mediaidentification symbols 205 (or simply the media identification symbols205). Furthermore, the media identification data conveyed by the firstgroup of symbols 205 (e.g., the media identification symbols 205) isrepeated in successive watermarks 200 embedded/included in the media.

In some examples, the first group of symbols 205 of the watermark 200includes example marker symbols 215A-B to assist the watermark detector145 in detecting the start of the watermark 200 in the watermarkedmedia, and example data symbols 220A-F to convey the mediaidentification data. Also, in some examples, corresponding symbols pairsin similar respective locations after the first marker symbol 215A andthe second marker symbol 215B are related by an offset. For example, thevalue of data symbol 220D may correspond to the value of data symbol220A incremented by an offset, the value of data symbol 220E maycorrespond to the value of data symbol 220B incremented by the sameoffset, and the value of data symbol 220F may correspond to the value ofdata symbol 220C incremented by the same offset, as well. In suchexamples, the symbols pairs 220A/D, 220B/E and 220C/F are referred to assymbol offset pairs, or offset pairs, and the offset used to generatethe symbol offset pairs forms an additional data symbol that can be usedto convey the media identification data.

In the example watermark 200 of FIG. 2 , the second group of symbols 210conveys timestamp data (e.g., a timestamp) identifying, for example, aparticular elapsed time within the watermarked media. Thus, in theillustrated example of FIG. 2 , the second group of symbols 210 is alsoreferred to as the second group of timestamp symbols 210 (or simply thetimestamp symbols 210). Furthermore, the timestamp data conveyed by thesecond group of symbols 210 (e.g., the timestamp symbols 210) differs insuccessive watermarks 200 embedded/included in the media (e.g., as theelapsed time of the watermarked media increases with each successivewatermark 200).

In the illustrated example of FIG. 2 , the watermark 200 isembedded/included in the desired media at a repetition interval of tseconds (or, in other words, at a repetition rate of 1/t seconds), withthe first group of symbols 205 remaining the same in successivewatermarks 200, and the second group of symbols 205 varying insuccessive watermarks 200 according to the time resolution supported bythe symbols 205. For example, the symbols 205 may support a timeresolution of one minute and, thus, will change on one minuteboundaries. For example, the repetition interval t may correspond tot=4.8 seconds. As there are twelve symbols in the example watermark 200(e.g., eight symbols in the first group of symbols 205 and four symbolsin the second group of symbols 210) each watermark symbol in theillustrated example has a duration of 4.8/12=0.4 seconds. However, othervalues for the repetition interval t may be used in other examples.

In some examples, a watermark symbol included in the watermark 200 isable to take on one of several possible symbol values. For example, if asymbol in the watermark 200 represents four bits of data, then thesymbol is able to take on one of sixteen different possible values. Forexample, each possible symbol value may correspond to a different signalamplitude, a different set of code frequencies, etc. In some suchexamples, to detect a watermark symbol embedded/included in watermarkedmedia, the example watermark detector 145 processes monitored mediadata/signals output from the example media device 110 to determinemeasured values (e.g., signal-to-noise ratio (SNR) values) correspondingto each possible symbol value the symbol may have. The watermarkdetector 145 then selects the symbol value corresponding to the best(e.g., strongest, largest, etc.) measured value (possibly afteraveraging across multiple samples of the media data/signal) as thedetected symbol value for that particular watermark symbol.

An example implementation of the media device meter 125 (e.g., which maybe a portable device) of FIG. 1 is illustrated in FIG. 3 . In theillustrated example of FIG. 3 , the media device meter 125 includes oneor more example sensor(s) 305 to detect media data/signal(s) emitted orotherwise output by the example media device 110. In some examples, thesensor(s) 305 include an audio sensor to monitor audio data/signal(s)output by the media device 110. Such an audio sensor may be implementedusing any type of audio sensor or audio interface, such as a microphone,a transducer, a cable/wire, etc., capable of receiving and processingaudio signals (e.g., such as in the form of acoustic and/or electricalsignals). Additionally or alternatively, in some examples, the sensor(s)305 include a video sensor to monitor video data/signal(s) output by themedia device 110. Such a video sensor may be implemented using any typeof video sensor or video interface, such as a camera, a light detector,a cable/wire, etc., capable of receiving and processing video signals(e.g., such as in the form of optical images and/or electrical signals).

The example media device meter 125 of FIG. 3 also includes the examplewatermark detector 145. In the illustrated example of FIG. 3 , thewatermark detector 145 is configured to detect watermarks, such as theexample watermark 200 of FIG. 2 , in the media data/signal(s) detectedby the example sensor(s) 305. In some examples, the watermark detector145 of FIG. 3 is structured to process audio data/signal(s) obtained bythe sensor(s) 305 to detect symbols of instances of the watermark 200that are encoded in one or more frequencies of the sensed audiodata/signal(s), or otherwise encoded in the frequency domain of thesensed audio data/signal(s). Examples of encoding watermarks in thefrequency domain of an audio signal, and corresponding example watermarkdetection techniques that may be implemented by the example watermarkdetector 145, are described in U.S. Pat. No. 8,359,205, entitled“Methods and Apparatus to Perform Audio Watermarking and WatermarkDetection and Extraction,” which issued on Jan. 22, 2013, U.S. Pat. No.8,369,972, entitled “Methods and Apparatus to Perform Audio WatermarkingDetection and Extraction,” which issued on Feb. 5, 2013, U.S.Publication No. 2010/0223062, entitled “Methods and Apparatus to PerformAudio Watermarking and Watermark Detection and Extraction,” which waspublished on Sep. 2, 2010, U.S. Pat. No. 6,871,180, entitled “Decodingof Information in Audio Signals,” which issued on Mar. 22, 2005, U.S.Pat. No. 5,764,763, entitled “Apparatus and Methods for Including Codesin Audio Signals and Decoding,” which issued on Jun. 9, 1998, U.S. Pat.No. 5,574,962, entitled “Method and Apparatus for AutomaticallyIdentifying a Program Including a Sound Signal,” which issued on Nov.12, 1996, U.S. Pat. No. 5,581,800, entitled “Method and Apparatus forAutomatically Identifying a Program Including a Sound Signal,” whichissued on Dec. 3, 1996, U.S. Pat. No. 5,787,334, entitled “Method andApparatus for Automatically Identifying a Program Including a SoundSignal,” which issued on Jul. 28, 1998, and U.S. Pat. No. 5,450,490,entitled “Apparatus and Methods for Including Codes in Audio Signals andDecoding,” which issued on Sep. 12, 1995, all of which are herebyincorporated by reference in their entireties. U.S. Pat. Nos. 8,359,205,8,369,972, U.S. Publication No. 2010/0223062, U.S. Pat. Nos. 6,871,180,5,764,763, 5,574,962, 5,581,800, 5,787,334, and 5,450,490 describeexample watermarking systems in which a watermark is included in anaudio signal by manipulating a set of frequencies of the audio signal.

In some examples, the watermark detector 145 of FIG. 3 is structured toprocess audio data/signal(s) obtained by the sensor(s) 305 to detectsymbols of instances of the watermark 200 that are encoded in one ormore time domain characteristics of the sensed audio signal, such as bymodulating the amplitude and/or phase of the audio signal in the timedomain. Examples of encoding watermarks in the time domain of an audiosignal, and corresponding example watermark detection techniques thatmay be implemented by the example watermark detector 145, include, butare not limited to, examples in which spread spectrum techniques areused to include a watermark in an audio signal. For example, such awatermark can be encoded in the audio signal by (1) spreading thewatermark by modulating the watermark with a pseudo-noise sequence andthen (2) combining the spread watermark with the audio signal. Detectionof such a watermark involves correlating the audio signal (after beingwatermarked) with the pseudo-noise sequence, which de-spreads thewatermark, thereby permitting the watermark to be detected after thecorrelation.

FIG. 4 illustrates an example mapping 400 of segments of a media signalover time. The first row represents the media segments 405(01-41) duringwhich a watermark 200 is broadcast. In the example mapping 400, eachmedia segment 405 may have, for example, a duration of five seconds.Thus, there are twelve segments in one minute of a media broadcast. Inother examples, other media segment durations may be used including, forexample, 4.8 seconds and/or any other desired amount. The “X” in thesecond row represents the watermarks 200 detected by the watermarkdetector 145. In this example, the watermark detector 145 detectseighteen watermarks 200. Some of the media segments 405 are notassociated with a detected watermark. In such examples, the signal mayhave been obscured by, for example, noise, and the watermark detector145 may not have been able to detect an associated watermark.

As shown in FIG. 3 , the example media device meter 125 also includes anexample timestamp decoder 310. The timestamp decoder 310 reads thetimestamp symbols 210 from the watermark 200 detected by the watermarkdetector 145. The time indicated by the timestamp symbols 210 isassociated with the media broadcast with which the detected watermark200 is broadcast. In the example mapping 400 of FIG. 4 , the timestampdecoder 310 having read the timestamps in the watermarks 200, determinesthat the time is T−1 in the second detected watermark 200 of the thirdmedia segment 405(03). In the third detected watermark 200 of theseventh media segment 405(07), the timestamp is T. The timestamp readsas time T until the timestamp decoder 310 determines the time is T+1 atthe seventh detected watermark 200 of the eighteenth media segment405(18). The detection and decoding process continues throughoutoperation of the media device meter 125. In the example shown, a timechange to T+2 is detected at the thirteenth detected watermark 200 ofthe thirty-first media segment 405(31), and a time change to T+3 isdetected at the seventeenth detected watermark 200 of the fortieth mediasegment 405(40).

With the information available from the watermark detector 145 and thetimestamp decoder 310, the media device meter 125 and/or data processingfacility 400 can determine estimated transition windows or coarsetransitions windows indicative of when the time of the media broadcastfor the associated media segment 405 advanced to the next time unit(e.g., next minute of the day). For example, the media device includesthe timestamp transition resolution enhancer 150 which has an exampletransition window estimator 315. The transition window estimator 315determines the estimated transition window based on a difference betweentwo detected watermarks. As shown in FIG. 4 , the time of the mediabroadcast is T−1 for the third media segment 405(03). At the seventhmedia segment 405(07), the detected watermark 200 indicates that thetime of the broadcast is T. Thus, the time changed from T−1 to T inbetween the broadcast of the third media segment 405(03) and the seventhmedia segment 405(07). As shown in FIG. 4 , there are several mediasegments 405(04-06) between the media segments 405 associated with thedifferent watermarks 200. In this example, these three media segments405(04-06) lack detected watermarks due to, for example, obfuscationsfrom noise. Thus, it is not known when exactly the time period switchedbetween T−1 and T. This could have occurred immediately after the thirdmedia segment 405(03) was broadcast up until the seventh media segment405(07) was broadcast. Thus, there is a window of time during which thetime transition occurred. In this example, the transition windowestimator 315 determines a first estimated transition window 410 betweentime T−1 and T.

The example timestamp transition resolution enhancer 150 also includesan example resolution comparator 320. The resolution comparator 320compares the duration of a transition window to a threshold to determineif the duration of the transition window meets the threshold. Thethreshold establishes the desired resolution of the timestamptransition. In the example where the media segments 405 of FIG. 4 have afive second duration, the first estimated transition window 410 is shownas twenty seconds. That is, the time switched from T−1 to T sometimeduring those twenty seconds. The resolution comparator 320 compares thetime period of twenty seconds to a threshold which may be set, forexample, at five seconds. That is, in this example, a timestamptransition resolution of five seconds is desired. In other examples, thethreshold is any desirable level of resolution. In this example, thetwenty second duration of the first estimated transition window 410 doesnot meet the threshold of five seconds. Thus, the timestamp transitionresolution enhancer 150 continues operation to improve the resolution ofthe time transition window. If the first estimated transition window 410does meet the threshold, the timestamp transition resolution enhancer150 sets the first estimated transition window 410 as the establishedtime transition or the baseline moment of transition.

During continued operation, the example transition window estimator 315determines subsequent time transitions and the corresponding transitionwindows. In the illustrated example, the example transition windowestimator 315 determines a second estimated transition window 415between the detection of time T at the sixth detected watermark 200 ofthe thirteenth media segment 405(13) and time T+1 at the seventhdetected watermark 200 of the eighteenth media segment 405(18). In thisexample, the second estimated transition window 415 is twenty-fiveseconds long, which is longer in duration than the first estimatedtransition window 410 and, therefore, alone does not improve thetimestamp transition resolution.

The timestamp transition resolution enhancer 150 also includes anexample mapper 325 that aligns or maps a reference transition windowwith an estimated transition window. For example, when the resolutioncomparator 320 determines that an estimated transition window does notmeet the threshold, the mapper 320 uses the estimated transition windowas a reference transition window and maps or aligns the referencetransition window with a subsequent estimated transition window. A firstestimated transition window can be used to predict subsequent estimatedtransition windows because the transitions between time periods iscyclical. A second estimated transition window and the first estimatedtransition window (used as a reference transition window) can be used torefine or improve the estimate of the timestamp transition.

In the example of FIG. 4 , the first estimated transition window 410 hasa duration of twenty seconds. When the media segments 405 are of a fivesecond duration, there are twelve segments in a minute. Thus, the firsttransition window 410 would indicate subsequent transition windows everyminute or twelve media segments 405. Thus, in this example, the firsttransition window 410 is used by the mapper 325 to predict, or estimate,a first reference transition window 420 by mapping the first estimatedtransition window 410 down twelve media segments 405 to form the firstreference transition window 420 in alignment with the second estimatedtransition window 415. More specifically, in the example mapping 400 ofFIG. 4 , the first estimated transition window 410 appears between thethird and sixth media segments 405(03-06). When the first estimatedtransition window 410 is mapped down (in this example one minute), thenext estimate for a window transition or the first reference transitionwindow 420 appears twelve media segments later or the fifteenth mediasegment 405(15) to the eighteenth media segment 405(18).

Based on the second estimated transition window 415, the timestamptransition resolution enhancer 150 can determine that a change in thetime period occurred between the watermark 200 detected in thethirteenth media segment 405(13) and the watermark 200 detected in theseventeenth media segment 405(17). However, the mapping of the firstestimated transition window 410 as the first reference transition window420 shows that the change in the time period occurred during one of thefifteenth to eighteenth media segments 405(15-18). With these twoestimates, the mapper 325 determines that the change in the time periodbetween T and T+1 occurred during the intersection of these two windows,namely, during the media segments 405(15-17) that overlap, or intersect,between the second estimated transition window 415 and the firstreference transition window 420, which forms a first mapped transitionwindow 425. Compared to the coarser first estimated transition window410 and second estimated transition window, the first mapped transitionwindow 425 represents a fine transition window in which the transitionresolution has been improved.

The resolution comparator 320 compares the first mapped transitionwindow 425 to the threshold. If the first mapped transition window meetsthe threshold, the timestamp transition resolution enhancer 150 sets thefirst mapped transition window 425 as the established time transition orthe baseline moment of transition. In the example of FIG. 4 , the firstmapped transition window 425 has a duration of fifteen seconds and failsto meet the threshold of five seconds.

If a desired level of resolution is not met, the timestamp transitionresolution enhancer 150 continues operation to improve the resolution ofthe time transition window, which includes repetition of one or more ofthe operations identified above. For example, in the illustratedexample, the example transition window estimator 315 determines a thirdestimated transition window 430 between the detection of time T+1 at thetwenty-sixth media segment 405(26) and time T+2 at the thirty-firstmedia segment 405(31). In this example, the third estimated transitionwindow 430 is twenty-five seconds long, which is longer in duration thanthe first mapped transition window 425 and, therefore, alone does notimprove the timestamp transition resolution.

The mapper 325 uses the first mapped transition window 425, to predict,or estimate, a second reference transition window 435 and aligns or mapsthe second reference transition window 435 with the third estimatedtransition window 430. In this example, the first mapped transitionwindow 425 occurs during the fifteenth, sixteenth, or seventeenth mediasegments 405(15-17). When mapped over an additional time period (e.g., aminute) as the second reference transition window 435, the duration fora subsequent timestamp transition is during the twenty-seventh,twenty-eight, or twenty-ninth media segment 405(27-29).

Based on the third estimated transition window 415, the timestamptransition resolution enhancer 150 can determine that a change in thetime period occurred between the twenty-sixth and thirtieth mediasegments 405(26-30). However, the mapping of the first mapped transitionwindow 425 as the second reference transition window 435 shows that thechange in the time period occurred during the twenty-seventh,twenty-eight, or twenty-ninth media segment 405(27-29). With these twoestimates, the mapper 325 determines that the change in the time periodbetween T+1 and T+2 occurred during the media segments 405 that overlapbetween the third estimated transition window 430 and the secondreference transition window 435, which forms the second mappedtransition window 440.

The resolution comparator 320 compares the second mapped transitionwindow 440 to the threshold. If the second mapped transition window 440meets the threshold, the timestamp transition resolution enhancer 150sets the second mapped transition window 440 as the established timetransition or the baseline moment of transition. In the example of FIG.4 , because the first mapped transition window 435 is wholly overlappedby the third estimated transition window 430, there is no furtherimprovement to the transition window resolution. Specifically, in thisexample, the transition window remains fifteen seconds and fails to meetthe threshold of five seconds.

As noted above, when a desired level of resolution is not met, thetimestamp transition resolution enhancer 150 continues operation toimprove the resolution of the time transition window. For example, inthe illustrated example, the example transition window estimator 315determines a fourth estimated transition window 445 between thedetection of time T+2 at the thirty-first media segment 405(31) and timeT+3 at the fortieth media segment 405(40). In this example, the fourthestimated transition window 445 is fifteen seconds long, which is notshorter in duration than the second mapped transition window 440 and,therefore, alone does not improve the timestamp transition resolution.

The mapper 325 uses the second mapped transition window 440 to predict,or estimate, a third reference transition window 450 and aligns or mapsthe second reference transition window 450 with the fourth estimatedtransition window 445. In this example, the second mapped transitionwindow 440 occurs during the twenty-seventh, twenty-eight, ortwenty-ninth media segment 405(27-29). When mapped over an additionaltime period (e.g., a minute) as the third reference transition window450, the duration of the subsequent timestamp transition is during thethirty-ninth, fortieth, and forty-first media segments 405(39-41).

Based on the fourth estimated transition window 445, the timestamptransition resolution enhancer 150 can determine that a change in thetime period occurred between the thirty-seventh and thirty-ninth mediasegments 405(37-39). However, the mapping of the second mappedtransition window 440 as the third reference transition window 450 showsthat the change in the time period occurred during the thirty-ninth,fortieth, and forty-first media segments 405(39-41). With these twoestimates, the mapper 325 determines that the change in the time periodbetween T+2 and T+3 occurred during the media segment 405 that overlaps,or intersects, between the fourth estimated transition window 445 andthe third reference transition window 450, which forms the third mappedtransition window 455. In this example, the third mapped transitionwindow 455 is the thirty-ninth media segment 405(39).

The resolution comparator 320 compares the third mapped transitionwindow 455 to the threshold. If the third mapped transition window 455does not meet the threshold, the timestamp transition resolutionenhancer continues through these operations to continue to improve theresolution. If the third mapped transition window 455 meets thethreshold, the timestamp transition resolution enhancer 150 sets thethird mapped transition window 455 as the established time transition orthe baseline moment of transition 460. In the example of FIG. 4 , thethird mapped transition window 450 has a duration of five seconds andmeets the threshold.

When a moment of time transition that meets the threshold is achieved,the established time transition 460 is determined. The established timetransition 460 is stored in a database 330 in the media device meter125, for example. The database 330 may be used for storage and retrievalof some or all data disclosed herein including, for example, data fromthe sensor(s) 305, the watermarks 200, the estimated transition windows410, 415, 430, 445, the reference transition windows 420, 435, 450, andthe mapped transition windows 425, 440, 455.

When the established time transition 460 is determined, the timestamptransition resolution enhancer 150 retroactively maps prior timetransitions in the media signal and/or proactively maps subsequenttransitions in the media signal based on the established time transition460. For example, in the mapping 400 of FIG. 4 , the established timetransition 460 is set at the thirty-ninth media segment 405(39). Thus,the transition between time period T+2 and time period T+3 occurredduring the thirty-ninth media segment 405(39). One unit of the timemeasurement divided into the media segments can be used to accuratelylocate the prior time transition, i.e., the transition between timeperiod T+1 and T+2. In the example of FIG. 4 , where the unit of timemeasurement is one minute and there are five second segments, thetimestamp transition resolution enhancer 150 counts back twelve segmentsand determines that the established transition 460 between time T+1 andtime T+2 occurred during the twenty-seventh media segment 405(27).Similarly, the timestamp transition resolution enhancer 150 determinesthat the established time transition 460 between time T and time T+1occurred during the fifteenth media segment 405(15), and the establishedtime transition 460 between time T−1 and time T occurred during thethird media segment 405(03).

In some examples, the timestamp transition resolution enhancer 150implements a voting scheme to assess the value of data. In this example,the timestamp transition resolution enhancer 150 discards dataindicative of errors. For example, data showing a decrease in a timevalue, data between watermarks of consecutive media segments showing amissed time unit (e.g., a skipped minute), and other erroneous orquestionable data can be ignored.

While an example manner of implementing the media device meter 125 ofFIG. 1 is illustrated in FIG. 3 , one or more of the elements, processesand/or devices illustrated in FIG. 3 may be combined, divided,re-arranged, omitted, eliminated and/or implemented in any other way.Further, the example watermark detector 145, the example timestamptransition resolution enhancer 150, the example sensor(s) 305, theexample timestamp decoder 310, the example transition window estimator315, the example resolution comparator 320, the example mapper 325, theexample databased 330, and/or, more generally, the example media devicemeter 125 of FIG. 3 may be implemented by hardware, software, firmwareand/or any combination of hardware, software and/or firmware. Thus, forexample, any of the example watermark detector 145, the exampletimestamp transition resolution enhancer 150, the example sensor(s) 305,the example timestamp decoder 310, the example transition windowestimator 315, the example resolution comparator 320, the example mapper325, the example databased 330, and/or, more generally, the examplemedia device meter 125 could be implemented by one or more analog ordigital circuit(s), logic circuits, programmable processor(s),application specific integrated circuit(s) (ASIC(s)), programmable logicdevice(s) (PLD(s)) and/or field programmable logic device(s) (FPLD(s)).When reading any of the apparatus or system claims of this patent tocover a purely software and/or firmware implementation, at least one ofthe example, watermark detector 145, the example timestamp transitionresolution enhancer 150, the example sensor(s) 305, the exampletimestamp decoder 310, the example transition window estimator 315, theexample resolution comparator 320, the example mapper 325, the exampledatabased 330, and/or the example media device meter 125 is/are herebyexpressly defined to include a non-transitory computer readable storagedevice or storage disk such as a memory, a digital versatile disk (DVD),a compact disk (CD), a Blu-ray disk, etc. including the software and/orfirmware. Further still, the example media device meter 125 of FIG. 3may include one or more elements, processes and/or devices in additionto, or instead of, those illustrated in FIG. 3 , and/or may include morethan one of any or all of the illustrated elements, processes anddevices.

A flowchart representative of example machine readable instructions forimplementing the media device meter 125 of FIG. 3 is shown in FIG. 5 .In this example, the machine readable instructions comprise a programfor execution by a processor such as the processor 1012 shown in theexample processor platform 1000 discussed below in connection with FIG.6 . The program may be embodied in software stored on a non-transitorycomputer readable storage medium such as a CD-ROM, a floppy disk, a harddrive, a digital versatile disk (DVD), a Blu-ray disk, or a memoryassociated with the processor 1012, but the entire program and/or partsthereof could alternatively be executed by a device other than theprocessor 1012 and/or embodied in firmware or dedicated hardware.Further, although the example program is described with reference to theflowchart illustrated in FIG. 5 , many other methods of implementing theexample media device meter 125 may alternatively be used. For example,the order of execution of the blocks may be changed, and/or some of theblocks described may be changed, eliminated, or combined. Additionallyor alternatively, any or all of the blocks may be implemented by one ormore hardware circuits (e.g., discrete and/or integrated analog and/ordigital circuitry, a Field Programmable Gate Array (FPGA), anApplication Specific Integrated circuit (ASIC), a comparator, anoperational-amplifier (op-amp), a logic circuit, etc.) structured toperform the corresponding operation without executing software orfirmware.

As mentioned above, the example processes of FIG. 5 may be implementedusing coded instructions (e.g., computer and/or machine readableinstructions) stored on a non-transitory computer and/or machinereadable medium such as a hard disk drive, a flash memory, a read-onlymemory, a compact disk, a digital versatile disk, a cache, arandom-access memory and/or any other storage device or storage disk inwhich information is stored for any duration (e.g., for extended timeperiods, permanently, for brief instances, for temporarily buffering,and/or for caching of the information). As used herein, the termnon-transitory computer readable medium is expressly defined to includeany type of computer readable storage device and/or storage disk and toexclude propagating signals and to exclude transmission media.“Including” and “comprising” (and all forms and tenses thereof) are usedherein to be open ended terms. Thus, whenever a claim lists anythingfollowing any form of “include” or “comprise” (e.g., comprises,includes, comprising, including, etc.), it is to be understood thatadditional elements, terms, etc. may be present without falling outsidethe scope of the corresponding claim. As used herein, when the phrase“at least” is used as the transition term in a preamble of a claim, itis open-ended in the same manner as the term “comprising” and“including” are open ended.

The example machine readable instructions 500 of FIG. 5 begin at block505 when the watermark detector 145 detects one or more watermarks 200from a media signal. The example timestamp decoder 310 decodes atimestamp (Tn) from the watermarks (block 510) (in some examples n isinitially set at 0). For example, the timestamp decoder 310 readstimestamps such as timestamp symbols 210 from the watermark 200. Theexample timestamp decoder 310 analyzes a media signal to detect andmonitor subsequent watermarks and timestamps (block 515). The exampletimestamp transition resolution enhancer 150 determines if a watermarkincludes a timestamp indicative of a change in time (Tn+1) (block 520).For example, the watermark 200 includes time symbols 210 that indicatethe time at which the watermark 200 and associated media content wasbroadcast. As the time of day progresses, the time symbols 210 change.Eventually, a subsequent watermark 200 will include a timestamp thatindicates a change of time from (Tn) to (Tn+1).

If a watermark 200 does not include a timestamp indicative of a changein time (block 520), the example timestamp decoder 310 continues todetect and decode watermarks and timestamps (block 515). However, if awatermark 200 does include a timestamp indicative of change in time(block 520), the example transition window estimator 315 of the exampletimestamp transition resolution enhancer 150 identifies an estimatedtransition window (Wn) (block 525). For example, the transition windowestimator 315 determines a duration of time or time window during whichthe time changed from one time period to a second time period based onthe duration between the two watermarks with disparate timestamps. Asdisclosed in the example above, the transition window estimator 315determines the first estimated transition window 410.

The example resolution comparator 320 of the example timestamptransition resolution enhancer 150 determines if the estimatedtransition window (Wn) meets or satisfies a threshold time duration(block 530). In some examples, the threshold is set at five seconds,though other values may be used. If the estimated transition window (Wn)is five seconds or less, in this example, the resolution comparator 320will determine that the threshold is met. In other words, the desiredresolution of estimating when a time transition occurred has beensatisfied. When the estimated transition window (Wn) is determined tomeet the threshold (block 530), the example timestamp transitionresolution enhancer 150 continues and sets the estimated transitionwindow (Wn) as the moment of time transition (block 535).

When the moment of time transition is set (block 535), the exampletimestamp transition resolution enhancer 150 retroactively and/orproactively sets prior and/or subsequent moments of time transitions(block 540). For example, the timestamp transition resolution enhancer150 sets the established moment of time transition 460 when theresolution threshold is met. Once a moment of time transition isestablished with the desired resolution, other moments of timetransition can be determined based on the number of media segments in atime unit. In the example disclosed above, there are five second mediasegments and, therefore, twelve segments in a minute. When the thresholdof five seconds (e.g., one media segment) is met, the timestamptransition resolution enhancer 150 sets the moment of time transition460 and can count forward and/or backward twelve media segments to markor otherwise note moments of other time transitions. When the moments oftime transition are marked to the desired resolution level, the exampleprogram 500 ends.

When the estimated transition window (Wn) does not meet the thresholdtime duration (block 530), the example timestamp transition resolutionenhancer 150 continues and sets the estimated transition window (Wn) asa reference transition window (block 545). For example, the timestamptransition resolution enhancer 150 sets the first estimated transitionwindow 410 as the first referenced transition window 420 when the firstestimated transition window 410 fails to meet the threshold.

The example timestamp decoder 310 and the example timestamp transitionresolution enhancer 150 continue and analyze the media signal to detectand monitor subsequent watermarks and timestamps (block 550) to detect awatermark including a timestamp indicative of a change in time (Tn+2)(block 555). If a watermark 200 does not include a timestamp indicativeof a change in time (block 555), the example timestamp transitionresolution enhancer 150 continues to detect and decode watermarks andtimestamps (block 550). However, if a watermark 200 does include atimestamp indicative of change in time (block 555), the exampletimestamp transition resolution enhancer 150 identifies an estimatedtransition window (Wn+1) (block 560). For example, the transition windowestimator 315 determines a duration of time or time window during whichthe time changes from a second time period to a third time period basedon the duration between the two watermarks with disparate timestamps. Asdisclosed in the example above, the transition window estimator 315determines the second estimated transition window 415.

Though not explicitly shown in FIG. 5 , in some examples, the exampletimestamp transition resolution enhancer 150 determines if the estimatedtransition window between the second time period and the third timeperiod meets the threshold similar to block 530. If the threshold ismet, the example program would continue through blocks 535 and 540 asdetailed above.

When the estimated transition window (Wn+1) is determined (block 560),and the estimated transition window (Wn+1) fails to meet the thresholdor is not compared to the threshold, the example mapper 325 of theexample timestamp transition resolution enhancer 150 maps or aligns thereference transition window (Wn) with the estimated transition window(Wn+1) (block 565). For example, the mapper 325 maps the first estimatedtransition window 410 as the first reference transition window 420 tothe second estimated transition window 415. The example timestamptransition resolution enhancer 150 determines an overlap between thereference transition window (Wn) and the estimated transition window(Wn+1) (block 570). For example, the timestamp transition resolutionenhancer 150 determines what media segments 405(15-17) overlap betweenthe media segments 405(15-18) broadcast during the duration of the firstreference transition window 420 and the media segments 405(13-17)broadcast during the duration of the second estimated transition window415. The example timestamp transition resolution enhancer 150 sets theoverlap as the mapped transition window (block 575). In the exampledisclosed above, the timestamp transition resolution enhancer 150 setsthe overlap between the second estimated transition window 415 and thefirst reference transition window 420 as the first mapped transitionwindow 425. In another example, the timestamp transition resolutionenhancer 150 sets the overlap between the fourth estimated transitionwindow 445 and the third reference transition window 450 as the thirdmapped transition window 455.

The example resolution comparator 320 of the example timestamptransition resolution enhancer 150 determines if the mapped transitionwindow meets a threshold time duration (block 580). In some examples,the threshold is set at five seconds, though other values may be used.If the mapped transition window is five seconds or less, in thisexample, the resolution comparator 320 will determine that the thresholdis met. In other words, the desired resolution of estimating when a timetransition occurred has been satisfied. When the mapped transitionwindow is determined to meet the threshold (block 580), the exampletimestamp transition resolution enhancer 150 continues and sets themapped transition window as the moment of time transition (block 585).In one of the examples disclosed above, the resolution comparator 320determines that the third mapped transition window 455 meets thethreshold of five seconds. The timestamp transition resolution enhancer150 sets the third mapped transition window 455 as the established timetransition 460.

When the moment of time transition is set (block 585), the exampletimestamp transition resolution enhancer 150 retroactively and/orproactively sets prior and/or subsequent moments of time transitions(block 540), as disclosed above. For example, the timestamp transitionresolution enhancer 150 sets the established moment of time transitions460 when the resolution threshold is met for other time transitionsduring the broadcast of the media signal. When the moments of timetransition are marked to the desired resolution level, the exampleprogram 500 ends.

If the mapped transition window fails to the meet the threshold timeduration (block 580), the example timestamp transition resolutionenhancer 150 sets the mapped transition window as the referencetransition window (Wn) (block 590). For example, when the first mappedtransition window 425 fails to meet the threshold of five seconds, thetimestamp transition resolution enhancer 150 sets the first mappedtransition window 425 as the second reference transition window 435.Thereafter, the example timestamp decoder 310 and the example timestamptransition resolution enhancer 150 continue to monitor the media signaland repeating the analysis by returning to block 550, after incrementingn (block 595) to indicate the subsequent time periods being analyzed.

The example timestamp decoder 310 and the example timestamp transitionresolution enhancer 150 continue execution until it is determined thatthe duration of the mapped transition window satisfies the thresholdsetting the desired resolution of a time transition window (block 580).When the threshold is satisfied, or the desired resolution is otherwisedetermined to be met, the example timestamp transition resolutionenhancer 150 proceeds through setting the mapped transition window asthe moment of time transition (block 585) and mapping prior and/orsubsequent time transition (block 540) as disclosed above until theexample program 500 ends.

FIG. 6 is a block diagram of an example processor platform 600structured to execute the instructions of FIG. 5 to implement the mediadevice meter 125 of FIG. 3 . The processor platform 600 can be, forexample, a server, a personal computer, a mobile device (e.g., a cellphone, a smart phone, a tablet such as an iPad™), a personal digitalassistant (PDA), an Internet appliance, a DVD player, a CD player, adigital video recorder, a Blu-ray player, a gaming console, a personalvideo recorder, a set top box, or any other type of computing device.

The processor platform 600 of the illustrated example includes aprocessor 605. The processor 605 of the illustrated example is hardware.For example, the processor 605 can be implemented by one or moreintegrated circuits, logic circuits, microprocessors or controllers fromany desired family or manufacturer. The hardware processor may be asemiconductor based (e.g., silicon based) device. In this example, theprocessor 605 implements the example watermark detector 145, the exampletimestamp transition resolution enhancer 150, the example timestampdecoder 310, the example transition window estimator 315, the exampleresolution comparator 320, and the example mapper 325.

The processor 605 of the illustrated example includes a local memory 610(e.g., a cache). The processor 605 of the illustrated example is incommunication with a main memory including a volatile memory 615 and anon-volatile memory 620 via a bus 625. The volatile memory 615 may beimplemented by Synchronous Dynamic Random Access Memory (SDRAM), DynamicRandom Access Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRAM)and/or any other type of random access memory device. The non-volatilememory 620 may be implemented by flash memory and/or any other desiredtype of memory device. Access to the main memory 615, 620 is controlledby a memory controller.

The processor platform 600 of the illustrated example also includes aninterface circuit 630. The interface circuit 630 may be implemented byany type of interface standard, such as an Ethernet interface, auniversal serial bus (USB), and/or a PCI express interface.

In the illustrated example, one or more input devices 635 are connectedto the interface circuit 630. The input device(s) 635 permit(s) a userto enter data and/or commands into the processor 605. The inputdevice(s) can be implemented by, for example, an audio sensor, amicrophone, a camera (still or video), a keyboard, a button, a mouse, atouchscreen, a track-pad, a trackball, isopoint and/or a voicerecognition system.

One or more output devices 640 are also connected to the interfacecircuit 630 of the illustrated example. The output devices 640 can beimplemented, for example, by display devices (e.g., a light emittingdiode (LED), an organic light emitting diode (OLED), a liquid crystaldisplay, a cathode ray tube display (CRT), a touchscreen, a tactileoutput device, a printer and/or speakers). The interface circuit 630 ofthe illustrated example, thus, typically includes a graphics drivercard, a graphics driver chip and/or a graphics driver processor.

The interface circuit 630 of the illustrated example also includes acommunication device such as a transmitter, a receiver, a transceiver, amodem and/or network interface card to facilitate exchange of data withexternal machines (e.g., computing devices of any kind) via a network645 (e.g., an Ethernet connection, a digital subscriber line (DSL), atelephone line, coaxial cable, a cellular telephone system, etc.).

The processor platform 600 of the illustrated example also includes oneor more mass storage devices 650 for storing software and/or data.Examples of such mass storage devices 650 include floppy disk drives,hard drive disks, compact disk drives, Blu-ray disk drives, RAIDsystems, and digital versatile disk (DVD) drives.

The coded instructions 655 of FIG. 5 may be stored in the mass storagedevice 655, in the volatile memory 615, in the non-volatile memory 620,and/or on a removable tangible computer readable storage medium such asa CD or DVD.

From the foregoing, it will be appreciated that example methods,apparatus and articles of manufacture have been disclosed that improveor enhance the resolution of a timestamp transition window. Mediasignals contain watermarks with timestamps indicative of the time ofbroadcast of the portion of the media signal associated with thewatermark. Media content providers and advertisers want to knowprecisely when their media was broadcast, and the timestamps in thewatermarks are used to provide this information.

In some prior watermarking solutions, the exact broadcast time of mediabroadcast in time slots smaller than the transition window will goundetected. For example, a transition window of one minute will notidentify exactly when an advertisement with a duration of twenty secondswas broadcast. An advertiser who paid for a twenty second advertisementspot at the beginning of a minute-long advertisement break would want toknow that their advertisement was in fact broadcast during the firsttwenty seconds of the advertisement break. This level of precisioncannot be provided when the timestamp transition window is too large.Examples disclosed herein improve the timestamp transition resolution toovercome the limitation of the prior art. In some examples, theresolution is improved to five seconds. The improved resolution enablesthe exact broadcast times of each moment of the media signal to bepinpointed down to the resolution threshold (e.g., 5 seconds). Thisimprovement has been developed and is usable without requiring thebroadcast of additional watermarks, enhanced detection techniques tocapture more watermarks, or a more finite segmentation of media signals.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent.

What is claimed is:
 1. An apparatus comprising: at least one memory;instructions on the apparatus; and at least one processor to execute theinstructions to at least: determine an initial resolution for timestamptransitions based on a first number of time units between first ones ofwatermarks detected in media; and determine an updated resolution forthe timestamp transitions based on a predicted timestamp transitionwindow and a second number of time units between second ones of thewatermarks detected in the media, the second ones of the watermarks tobe subsequent to the first ones of the watermarks in the media, thepredicted timestamp transition window associated with the initialresolution for timestamp transitions, the updated resolution for thetimestamp transitions corresponding to a third number of time units, thethird number of time units less than the second number of time units. 2.The apparatus of claim 1, wherein at least one of the second number oftime units overlaps one of the third number of time units.
 3. Theapparatus of claim 1, wherein the at least one processor is to determinea fourth number of time units between fourth ones of the watermarksdetected forward in the media based on the updated resolution for thetimestamp transitions.
 4. The apparatus of claim 1, wherein the at leastone processor is to determine a fourth number of time units betweenfourth ones of the watermarks detected backward in the media based onthe updated resolution for the timestamp transitions.
 5. The apparatusof claim 1, wherein the third number of time units is about 5 seconds.6. The apparatus of claim 1, wherein the at least one processor is todetermine the updated resolution for the timestamp transitions based ona threshold.
 7. The apparatus of claim 6, wherein the threshold is onetime unit.
 8. A system comprising: means for detecting watermarks inmedia; and means for determining resolutions for timestamp transitions,the means for determining to: determine an initial resolution for thetimestamp transitions based on a first number of time units betweenfirst ones of the watermarks detected in media; and determine an updatedresolution for the timestamp transitions based on a predicted timestamptransition window and a second number of time units between second onesof the watermarks detected in the media, the second ones of thewatermarks to be subsequent to the first ones of the watermarks in themedia, the predicted timestamp transition window associated with theinitial resolution for timestamp transitions, the updated resolution forthe timestamp transitions corresponding to a third number of time units,the third number of time units less than the second number of timeunits.
 9. The system of claim 8, wherein at least one of the secondnumber of time units overlaps one of the third number of time units. 10.The system of claim 8, wherein the means for determining is to determinea fourth number of time units between fourth ones of the watermarksdetected forward in the media based on the updated resolution for thetimestamp transitions.
 11. The system of claim 8, wherein the means fordetermining is to determine a fourth number of time units between fourthones of the watermarks detected backward in the media based on theupdated resolution for the timestamp transitions.
 12. The system ofclaim 8, wherein the third number of time units is about 5 seconds. 13.The system of claim 8, wherein the means for determining is to determinethe updated resolution for the timestamp transitions based on athreshold.
 14. The system of claim 13, wherein the threshold is one timeunit.
 15. A non-transitory computer readable medium includinginstructions which, when executed, cause a machine to at least:determine an initial resolution for timestamp transitions based on afirst number of time units between first ones of watermarks detected inmedia; and determine an updated resolution for the timestamp transitionsbased on a predicted timestamp transition window and a second number oftime units between second ones of the watermarks detected in the media,the second ones of the watermarks to be subsequent to the first ones ofthe watermarks in the media, the predicted timestamp transition windowassociated with the initial resolution for time stamp transitions, theupdated resolution for the timestamp transitions corresponding to athird number of time units, the third number of time units less than thesecond number of time units.
 16. The computer readable medium of claim15, wherein at least one of the second number of time units overlaps oneof the third number of time units.
 17. The computer readable medium ofclaim 15, wherein the instructions are to cause the machine to determinea fourth number of time units between fourth ones of the watermarksdetected forward in the media based on the updated resolution for thetimestamp transitions.
 18. The computer readable medium of claim 15,wherein the instructions are to cause the machine to determine a fourthnumber of time units between fourth ones of the watermarks detectedbackward in the media based on the updated resolution for the timestamptransitions.
 19. The computer readable medium of claim 15, wherein thethird number of time units is about 5 seconds.
 20. The computer readablemedium of claim 15, wherein the instructions cause the machine todetermine the updated resolution for the timestamp transitions based ona threshold.